Give an example of a schedule of two transactions in which a two-phase locking concurrency control
a. makes one of the transactions wait, but a control implementing SNAPSHOT isolation aborts one of the transactions.
b. aborts one of the transactions (because of a deadlock), but a control implementing SNAPSHOT isolation allows both transactions to commit.
a. r1(x) w1(x) r2(y) w2(x) commit2
A two-phase locking concurrency control would make T2 wait, but a SNAPSHOT isolation control would abort T1, since T2 was the first committer.
b. r1(x) r2(y) w2(x) w1(y)
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